The present invention relates to apparatus and methods for mitigating electromagnetic interference (EMI) in electrical circuits.
Electrical circuits such as integrated circuits are used in a wide variety of different environments. As a result, special efforts are needed to develop electrical circuits that can function properly in their intended operational environments. Many electrical circuits operate in harsh and/or noisy environments, which can lead to issues with electromagnetic interference (EMI). EMI may include any unwanted, spurious, conducted, or radiated signal that can cause an undesired degradation in the performance of an electrical circuit. Electromagnetic compatibility (EMC), on the other hand, is the ability of an electrical circuit to function as designed, without malfunctioning or exhibiting unacceptable performance degradation as a result of EMI that may be present in its operating environment. Examples of EMI performance degradation include a computing device interfering with FM radio reception or an automobile radio system buzzing upon passing under a power line. In general, electrical circuits should be designed such that they do not generate EMI in amounts that adversely affect the performance of other electrical circuits in their vicinity and vice versa.
In the United States, Congress has granted the Federal Communications Commission (FCC) authority to regulate the susceptibility of electrical circuits to EMI in the U.S. The FCC also regulates the amount of EMI that electrical circuits are allowed to generate in the U.S. Special efforts are needed to ensure that electrical circuits comply with these regulations. As a result, controlling and mitigating EMI is a key consideration when designing many electrical circuits.
In view of the foregoing, what are needed are apparatus and methods to mitigate EMI emitted from electrical circuits such as integrated circuits. Ideally, such apparatus and methods would be able to reduce EMI directly at the micro-electronic-component level, such as at the integrated-circuit level.